[Text of letter dated 4th August 2001, to The Editor, the New York Times.]
I read with great interest your 29th July article on cyclist injuries. Having had one paper on the topic published in the British Medical Journal [BMJ 2000;321:1582-5] and one letter [BMJ 2001;322:1063], with a futher paper under Peer Review, I may be able to add useful information.
It is important to understand that the risks of road cycling are greatly overestimated. Where good data exist, it may be shown that the hourly risk of death when cycling is similar to that for car users. For instance, official statistics show that in the Netherlands and Denmark, cycling is safer than driving. In France, an hour of cycling is three times safer than driving, even though French cyclists share road space with French drivers. In Germany, there is parity of risk, while in Great Britain, an hour of average cycling incurs 2.5 times the risk of death when driving, but here the comparison is biased because half of British cyclists are young males. Accounting for this bias suggests that British cyclists face risks no greater than the European average for car occupants, or for US car occupants. In Great Britain, a mile of walking is more likely to kill you than a mile of cycling.
Extending the safety discussion, cyclists very rarely inflict fatal injuries on others, whereas the scale of injuries inflicted by motor vehicles is notorious. When third party fatalities are included in the calculation, the safety advantage swings decisively to the bicycle in all countries for which I have data.
The most effective means to improve cyclist casualty rates is to increase the number of cyclists on the roads. In Great Britain, the amount of cycling increased by 70% between 1972 and 1982, during which period cyclist fatalities actually fell by 10%. The more cyclists there are, the safer cycling is. To select cyclists alone to wear helmets is to apply a double standard that confuses the public estimate of the risks, thus deterring cycling. Ironically, cycle helmet promotion is thus the major obstacle to safer cycling, and as your article pointed out, helmet use has made existing conditions worse.
There were several developments during 1999 that must be mentioned. Two research teams announced their evaluations of the effects of helmet use in New Zealand and Australia. Both of these studies covered periods of growth in helmet wearing from zero up to high levels following laws compelling use by cyclists of all ages. Although both studies claimed small levels of prevention of serious head injury (10-20%), close inspection of the results leaves one doubtful, since the reductions either did not correspond with changing levels of helmet use, or else referred mainly to scalp lacerations, which are not intracranial injuries. The British Medical Association published its review of cycle helmets in 1999. In this 38 page booklet, just over one page is devoted to discussion of helmet effectiveness, and half of that is to warn of the danger of near-instantaneous helmet failure upon hard impact. There is no estimate given of prevention of serious head injury. Although some experts still claim very high levels of protection from helmets, the BMA is no longer prepared to cite such claims. This is a fair reaction to real world experience.
The situation in Great Britain parallels that in the USA. Road casualty statistics show that during the period 1970-93, when helmet use was negligible, cyclists had the fastest-improving safety record of any class of road user, but since helmets have come into use, cyclists have had the worst of safety records. Cyclists deaths and serious injuries increased by 20-30% as helmets became popular in 1993-95. This unfortunate development has yet to register with official policy makers, who persist in promoting cycle helmets.
Cycle helmets do have a place in reducing injuries for certain types of cycling - but the issue needs candid debate founded on acceptance of real world experience. I do not wear a helmet for road riding. Instead, I rely on cultivating the highest levels of proficiency. I believe I am making an informed choice, given the type of riding I pursue; the balance of evidence points my way.